Zero entropy

I know that when the number of moles of gases increases, entropy increases and when we go from solid to liquid to gas, entropy increases. But I am wondering under what circumstances is entropy zero? The only example I can think of is that if the number of moles of a given phase does not change, then entropy would be zero. eg. 2A (g) + 3B(g) -> 4C(g) + 1D(g) Entropy would be zero here since the total number of moles of gas (5 moles) remains the same. Are there any other situations where...

Zero entropy